Shock absorber



Jun 3, 1930. J. F. ocoNNoR 1,761,272

socx ABsomaER Filed July 29. 192s Patented June 3, 1930 UNITED STA-'rss PATENT l OFFICE JOHN I'. OCONNOB, GF CHICAGQ'ILLINOIS, ASSIGNOB T0 W. H. EINER, INC., 0l

` CHICAGO, ILLINOIS, A CORPORATION F DELAWARE SHOCK ABSOBBEB Application flied viluly '29,

This invention relates to improvements in shock absorbers, and more particularly to shock absorbers adaptedA for railway cars.

As is well known to those skilled in the art of railway rolling stock and equipment, there has been from year to year a gradual increase in the size of railway'cars and a corresponding increase in load carrying capacity for cars, until service conditions have become 1o such as to tax the ca acity of truck springs possible to employ. asmuch as the space which may be occupied by the trucksprings of cars is very strictly limited by regulations of standardization, and therefore the size and number of springs that may be employed cannot exceed a certain limit, it is common that the springs ordinarily employed are compressed to such an extent when the cars are fully loaded that they afford very little cushioning effect where the car is in motion. Breakage of the springs in service frequently occurs due to the same being constantly overloaded, by impact.

' Itis one object of my invention to provide an arrangement of shock absorber or cushioning means for railway car trucks, which includes a dampening feature, land which functions when car is passing over an uneven track, or subject to other sudden increases of load.

Another-object of the invention is to prov ide a cushioning means of high capacity .for

'i car trucks, including friction means acting in conjunction with spring means, wherein the friction means is operative only when the added compression beyond static position, exceeds a certain amount, within the free action of the spring, and permitting return of the parts without frictional resistance dur- 40 ing recoil of the springs. This static posiv tion is set automatically by the load, and allows the same amount of vertical reciprocation, in any position, between that of a light and fully loaded car.

Still another object of the invention is to provide a shock absorbing means for-trucks of cars, including friction means in combination with spring means wherein a certain amount of preliminary compression of the springs is permittedv to take care of the 1926. Serial No. 125,605.

lighter shocks, before the friction means becomes operative ,to vtalle care of excessively heavy shocks. Y. A

More specifically, an object of my invention is to provide in a cushioning means for car trucks, friction means acting in combination with spring means, wherein the friction: means is of the rotative, screw operated type. and is operative only during compression of the cushioning means. Other objects and advantages of my invention will more fully and clearlya pear from a description and claims hereina Y er follow- 1n n the drawings, forming a part of this specification, Figure 1 is a transverse, vertical, sectionalV view through a portion of a 4car truck, illustrating an embodiment of my invention in connection therewith and at the end of the free downward spring action. Figure 2 is a horizontal sectional view cor, responding substantially to the line 2--2 of Figure 1. Figure 3 -is a view similar to Figure 1, partly broken away, illustrating another embodiment of my invention also at end of free spring closure. And Figure 4.

is a vertical, sectional view throu h a friction element and central spring mem er of a still further embodiment of my invention, showing it in full release under static load.

In said drawings, referring first to the embodiment of the invention illustrated in Figures 1 and 2, 10 designates theusual spring plank'of a car truck, which as is well known ears on the side frame proper of the truck. 35 y 11 indicates the bottom side of the usual truck bolster. My improved shockabsorbing mechanism is interposed between the Itruck bolster 11 and the spring plank 10 as is usual.

My improved shock absorbing or cushionno ing means comprises broadly: A top spring plate or follower A; a bottom spring plate or follower B; a cylindrical internally threaded member C.; a friction screw D ;'a friction disc E; a pair of friction plates F-F; and flve` spring elements G. i The spring. elements G, which are of the usual truck springftype, are interposed be- 1 tween the top s ring ollower plate A and the bottom spring ollower plate B. The arrangementof the five springs, com rising a lcentral sprin and four springs isposed about the centra s ring, is common and well 'known in this art. n order to increase the capacity of this spring arrangement, I employ in addition thereto a friction means comprising the internally threaded cylinders C, screw D and co-o erating friction plates E, F and F.y

Tge top spring plate or follower A is of the usual form employed in connection with the five spring arrangement and bears on the lower side of the truck bolster 11.

The bottom spring plate or follower B is in the form of a relatively heavy substaitially` rectangular block having a square recess 12k on the upper side thereof as most clearly shown in Fi re 2. The recess 12 is adapted to accoxnmo ate the two square friction plates F--F as more fully hereinafter described. The spring follower plate B rests directly on the upper face of the spring plank 10. The

, friction cylinder C is hollow as shown and is internally threaded as designated by 13, the threads 13 being of relatively steep pitch. Inthe form of the inventionillustrated in Figures 1 and 2, the threads 13 are of the triple co-operate with the threads 13 of the cylinder C. At the lower end, the screw D is provided with a disc like head or enlargementv 15 having clutch teeth 16 at the lower side thereof. The clutch teeth 16 of the head 15 co-operate with similar teeth 17 on an upwardly projecting boss 18 formed inte ral with the friction disc E.

he friction disc E rests upon the lowermost friction plate F and the upper fric-A tion plate F rests on topy of the disc E and has 'a central circular opening 19 adapted to accommodate the boss 18. The boss 18 is also rovided with an upwardly projecting cylin rical stem 20 extending into. the lower end of the screw D to properly center the parts.

As clearly shown in the drawings, the lower end of the hollow cylindrical screw C is spaced an appreciable distance from the upper" face of the head 15 on the screw D and the up er end of the screw D `terminates some istance from the top end threaded hollow portion of the cylinder. ,As will be clear from Figure 1, the threads on the screw and cylinder are so arranged and the co-operating clutch teeth 16 and 17 are so displosed that .the screw D will be rotated in vsue a dlrectlon as to interlock the clutch teeth and compel rotation ofthe diie E with the screw as the 'top follower plate A is moved downwardly toward the bottom plate B, beyond the position shown in Fig. l.

The central spring G bears directly at its up er end on the flan e 14 of the cylinder C an at its lower end irectly on the topmost friction plateV F. The remaining springs G are interposed directly between the top spring 4follower late A and the bottom spring follower p ate B.

In the operation of my improved device, as shown in Figures 1 and 2, when the truck bolster 11 and the spring plank 10 approach each other in the usual manner during the operation of the car, the sprin G will all be compressed. As the sprin ollower plates approach each other, the cy inder C will also approach the head 15 of the screw D and due 'to the interengaging threads of these parts, vthe head 15 will be rotated when the vertical play exceeds the depth of the clutch teeth, communicating rotation to the friction disc E by means of the interengaging clutch teeth 16 and 17. The friction disc E will thus be rotated with reference to the frictionl plates F which are held stationary.y It will be evident that rotation of the plates F will be prevented due to their square outline, these plates snugly fitting the square recess 12 of the lower spring plate or follower B. While the followers'A and B ap roach 4each other, friction will be created etween the interengaging threads of the screw D and the cylinder C in addition to the friction created between y the friction disc E and the discs F, thereby augmenting the resistance offered by the five springs G. Compression of the springs will be limited by engagement of the lower end of the cylinder C with the head 15 of the screw.

When the shock or shocks have been absorbed, the springs G will act to return the partsto their normal position. During this time, there will be no frictional resistance created inasmuch as the co-operating clutch teeth of the screw and friction disc E are free to disengage, permitting the screwD to be lifted with the cylinder C with slight rotation. When the negative truck bolster has been returned to normal position, the screw D will automatically adapt itself to proper position, permitting the prescribed free vertical oscllations, which are sufficient for normal runningl conditions.

The clutch teeth`16 and 17 will come into engagement at and rest, at some intermediate position. With the parts in this last named position, the screwwill not be actuated durin the initial ap roach or recession of the truc c bolster-11 an the spring plank 10 and there will be compression of the springs G only until such a time when the teeth 16 and 17 are forced into full engagement or the position shown in Figure 1. After the teeth have engaged and positively locked the head 1 5 t0 izo esv

' follower the friction plate E, the latter will be rotated in the manner hereinbefore described.

It will be evident that a preliminary spring action is thus available to absorb the lighter shocks under normal conditions, the heavier frictional resistance coming into action only when relatively heavy shocks are :encoun tered. 1 l

Referring next to the embodiment of the in vention illustrated in Fi re 3, the mechanism shown is substantially t e same as that illustrated in Figures 1 and 2 with the exception that the interengaging teeth on the screw and the friction disc are reversely inclined. In, Figure 3, B Adesignates the lower spring follower plate which has the square friction lates F- \mounted in an aperture 112 1n the top of the plate. The friction disc is designated by E and is provided with an upstanding cylindrical boss having clutch teeth 117 co-operating with clutchv teeth 116 on the head 115 formed integral `with the lower end of the screw D which co-o erates with the hollow threaded cylinder C The cylinder C is preferably mounted on the top late in the same manner as the cylinder described in connection with the embodiment of the invention illustrated in Figures 1 and 2. f

The device illustrated in Figure 3 is associated with a central spring G similar to central spring G hereinbefore referred to, and four additional springs disposed about the central spring G are employed in a man.- ner similar to the four outer springs G here,J

inbefore described.

rlhe operation of the device illustrated in Figure 3 is substantially the same as that of the device described in connection with Figures 1 and 2, the inclination ofthe interengaging faces of the clutch teeth 116 and 117 eing such as to prevent relative rotation of the screw D. and the friction disc E when the truck bolster and the spring plank are moved relatively to each other and within their depth. To effect rotation of the friction lplate the teeth must be fully meshed and then ave additional action of the truckbolster in downward direction.

Referring next to the embodiment of the invention illustrated in Figure '4, Adesignates the top sprin follower plate and B2 the bottom sprm fol ower plate. Attached to `the s ring fo lower plate A2 isa hollow interna ly threaded cylinder C2 in all respects similar tothe cylinder C hereinbefore described. A screw D2 co-operates with the threads of the cylinder. Five springs are interposed between the follower casings A2 and B2 in a manner similar to that shown in Figures 1 and 2, thementral spring of the group being designated by G2. The spring G2 is interposed between a fiange 214 at the u per end of the cylinder C2 and a friction dlsc- E2 bearing directly on top of the lower s ring follower plate B2. AThe friction disc 21s provided with an upwardly extending boss 218 having a fiat upper face. The disc E2 is also provided with a centrally disposed upwardly extending stem 220 projecting into a cylindrical opening 221 at the lower end of the screw D2. e The screw D2 is anchored lto the cylinder C72-by a retainer bolt 222 extending through a vertical bore in the screw and having the threaded end thereof disposed within the opening 221, the nut of the bolt being disposed in' a suitable recess at the top end of the cylinder C2. The'bolt 222 is of such a length as to permit a certain amount o f relative movement of the cylinder and the screw.

'In the normal position of the parte as shown in Figure 4, the bolt 222 supports the screw D in a partly raised position so that the lower end thereof is spaced from the up er face of the boss 218 onthe disc E2. It wi l be evident that during the initial approach of the truckbolster and the sprin lank, the springs between the plates A an li will be compressed without any relative movement between the screw D2 and the cylinder C2 being effected. After the springs have been compressed, to a certain extent, the lower end of the screw D2 will engage the upper face of the enlargement 218 on the friction disc E2, thereby arrestin furtherdownward movement of the screw 2. During the further approach of the spring l follower lates A2 and B2, rotation of the screw D2 will e effected through the interengaging threads of the screw and cylinder. y Friction will-thus be created between 4these threads. will further be created between the lower end Friction of the screw and the top surface of the boss 218.. Due to the friction between the lower end of the screw D2 and theupper face of the boss 218,` it is also possible that a slight rotation of` the friction disc E2 will be effected. yIn the latter case, friction will be created between the bottom face of this disc and the. spring follower plate B2. When the shock has been absorbed, the springs will re- -turn the parts to the normal position shown .in Figure 4. There will be no frictional reby the during approach of thetruck bolster and` sp1-ink' plank, but oer's no frictional resistance to the .free return of the parte.

due to While I have herein shown and described,

what I now consider the preferred manner of carrying out my invention, the same is merely illustrative, and I contemplate all changes and modifications that come within the scope of the claims appended hereto.

I claim:

1. In a shock absorber, the combination with spring followers movable relatively toward and away from each other, the combination with cushioning sprin means interposed between said followers o `a friction device interposed between said followers, said friction device including relatively rotatable screw and nut elements, one of said elements beingr fixed to one of the followers and'the other of said elements bein freely rotatable with respect to the other e ement under the action of gravity when said followers are zo separated and'adapted to engage one of said followers upon relative approach of the same to effect positive relative rotation of said screw elements.

2. In a shock absorbing mechanism, the

combination with relatively movable spring follower plates of spring means interposed between said follower plates; co-operating friction screw element-s, one of which is fixed to one of said spring followerplates and the so other of which is normally freely rotatable; and rotary friction means engaging the other follower plate and cooperating with said screw to retard rotary movement thereof upon relative approach of said followers.

3. In a shock absorbing mechanism, the combination with relatively movable spring follower elements; of spring means interposed between said elements and opposing relative approach of the same co-operating 40 friction screw elements, one of which is fixed to one of said followers and the other of which is relatively movable; and means operative upon relative movement of the bolsters toward each other, after a predetermined compression of the spring means to frictionally oppose rotation of said movable screw element, said last named means being inactive during movement of said holsters away from each other under the influence of the spring a means.

4. In a shock absorber for railway car trucks, the combination with follower members movable toward and away from each other; of sprin means opposing relative approach of sai follower members; friction means including relatively movable friction elements interposed between said follower members, one of said friction elements being movable with one of said follower members and the cooperating friction element being entirely disconnected from the other follower and freely movable away from the same during movement of said follower members away from each other, said last named element being normally spaced from said last named follower membei` to provide for preliminary action during the first part of the relative movement of said follower members toward each other, and adapted to be enga ed v by one of said follower members toe ect relative movement of/the friction elements during the further movement of the followers toward each other.

5. In a shock absorber, the combination with a pair of followers relatively movable toward and away from each other; of sprin means opposing relative approach of said fo lowers; a pair of interengaging cooperating friction screw elements, one of said elements being fixed to one.of said followers and niovable in unison therewith toward the other follower, and the other screw element being movable with respect to said follower; and means for limiting relative separation of said screw elements to hold said movable screw elements lspaced from said other follower when said followers are separated to the full means including a central coil and a plurality of coils surrounding said central coil; friction means interposed between said followers, said means being disposed within said central coil, said friction means including a friction element which is movable with one of said followers and a cooperating friction element which is movable with respect to said first named element; and means for Hunting relative separation of said friction elements, to hold the second named friction element spaced from the other follower when said followers are separated to the full extent of their movement, said spacing being less than the full amount of relative movement of said followers, whereby said last named friction element engages the cooperating follower to effect relative movement of said friction elementsA ers and the other of which is actuated by en-' gagement with the other follower, said second named element being freely movable away from said last named follower at yall times during movement of said followers away from each other; and spring means operating independently of said friction device yieldingly opposing approach of said followers, said spring means returning said followers to normal separated condition without actuating said friction device.

8. In a shockabsorbing mechanism for car trucks, the combination with a cushioning spring unit for supporting the car body on the truck, said cushioning spring unit including a central coil and four additional coils surrounding said central coil, said four additional coils being of standard size; of friction means, including relatively rotatable friction elements disposed entirel within said central coil, operated during re ative approach of said followers and compression of said cushioning means. In witness that I claim the foregoing I have hereunto subscribed my name this 27th day of July, 1926.

JOI-IN F. OCONNOR. 

